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Breast Changes During Pregnancy, Week by Week

Updated: Nov 25

Pregnancy brings about significant changes in a woman's body, and one of the most noticeable transformations occurs in the breasts. Throughout the nine months, breast changes are inevitable and play a crucial role in preparing for breastfeeding.

But these changes are normall, so don't freak out if you see something you've never seen before.

pregnant woman

Image created by Dalle-E

I've covered the changes week by week making it easier for you to recognize what is normal and what looks off.


In this article:


Weeks 1-4: Early Signs of Breast Changes

In the initial four weeks of pregnancy, changes in your breasts may not be readily apparent, but important processes are occurring.

Hormonal fluctuations, primarily due to rising levels of hCG, can lead to breast tenderness or soreness. You may also notice mild swelling in the breast area.

Weeks 5-8: Size and Sensitivity

As the second month begins, breast changes become more noticeable. Your breasts may feel fuller and more sensitive to touch. This heightened sensitivity is largely attributed to increased estrogen and progesterone levels.

Additionally, the areolas—the darker skin around your nipples—may enlarge and darken. Veins beneath the surface become more visible as blood flow increases in preparation for future milk production.

Weeks 9-12: Growth and Preparation

Entering the third month, breast growth continues, and mammary glands develop for future milk production. You might notice your bras no longer fit comfortably, requiring the transition to more supportive maternity bras.

The darkened areolas and Montgomery's tubercles, small raised bumps on the areola, remain prominent as they serve essential functions in breastfeeding.

Weeks 13-16: Colostrum Production

By the fourth month, your body begins producing colostrum, a nutrient-rich substance that will nourish your newborn during the initial days after birth.

Some women might experience colostrum leakage from their nipples. This is a normal and expected occurrence as your body gears up for breastfeeding.

Weeks 17-20: Rapid Growth

During the fifth month, many women experience a significant acceleration in breast growth. Your breasts may become noticeably larger than they were pre-pregnancy. This increased size can lead to stretch marks appearing on the breast skin.

Ensuring you wear a comfortable and supportive bra becomes essential to manage added weight and alleviate breast soreness.

Weeks 21-24: Preparing for Milk Production

In the sixth month, your body continues preparing for milk production. You may feel your milk ducts growing and becoming more prominent beneath the skin. Although breast sensitivity might decrease compared to earlier in your pregnancy, your breasts will remain larger than their pre-pregnancy size.

pregnant woman in nature

Image created by Dalle-E

Weeks 25-28: Colostrum Supply

As you approach the final trimester, colostrum production continues to increase. Colostrum leakage may become more frequent, especially when applying pressure to your breasts. Using nursing pads can help prevent any unintended leaks and keep your clothing dry.

This is also an ideal time to explore prenatal breastfeeding classes to understand the mechanics of breastfeeding better.

Weeks 29-32: Increased Blood Flow

In the eighth month, there's a surge in blood flow to your breasts, which can make them feel larger and more tender. The darkening of the areolas and the visibility of veins persist. Investing in comfortable nursing bras is essential during this time as your body gets ready for the postpartum period.

Weeks 33-36: Nesting and Preparation

As you approach the final weeks of pregnancy, the nesting instinct may kick in, prompting you to prepare your home for the baby's arrival.

Setting up a comfortable nursing area complete with breastfeeding pillows, nursing pads, and soothing music can help you feel more at ease and ready for the breastfeeding journey ahead.

Weeks 37-40: Ready for Nursing

In the ninth month, your breasts are fully prepared for breastfeeding. Colostrum production is at its peak, and you may experience Braxton Hicks contractions as your body gets ready for labor.

Having a breastfeeding plan in place, understanding proper latching techniques, and ensuring you have a strong support system can help you approach the delivery date with confidence.

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